. >> this is possibly the greatest cluster that has occurred certainly in the united states that i'm aware o of. >>reporter: early symptoms can take up to 6 weeks to the appear. include fatigue. fever and chills. those quickly give way to coughing and breathing problems as the lungs fill with fluid. the worst part is, there is no known treatment or cure. >> there's really nothing you can do preemptively if you were exposed to hantavirus. >>reporter: for one of america oldest and most popular national park a serious threat. yosemite majestic beauty attracts visitors worldwide. now that could mean a worldwide public health hazard. david wright abc news los angeles. >> man police describe as the instigator of gang rape near richmond high school has pleaded guilty to escape life in prison. 22 year old manuel ortega will serve 32 years in prison. he was the first of 6 defendants to stand trial in this 2009 rape that made national head liens. in october of that year a girl leaving a homecoming dance was raped and beaten for 2 hours with no one coming to her aid and others watching. ortega